Doesn't pgstat_report_wal() handle the argument "force" incorrectly
Ryoga Yoshida <bt23yoshidar@oss.nttdata.com>
From: Ryoga Yoshida <bt23yoshidar@oss.nttdata.com>
To: pgsql-hackers@lists.postgresql.org
Date: 2023-09-22T04:58:37Z
Lists: pgsql-hackers
Hi,
pgstat_report_wal() calls pgstat_flush_wal() and pgstat_flush_io(). When
calling them, pgstat_report_wal() specifies its argument "force" as the
argument of them, as follows. But according to the code of
pgstat_flush_wal() and pgstat_flush_io(), their argument is "nowait" and
its meaning seems the opposite of "force". This means that, even when
checkpointer etc calls pgstat_report_wal() with force=true to forcibly
flush the statistics, pgstat_flush_wal() and pgstat_flush_io() skip
flushing the statistics if they fail to acquire the lock immediately
because they are called with nowait=true. This seems unexpected behavior
and a bug.
void
pgstat_report_wal(bool force)
{
pgstat_flush_wal(force);
pgstat_flush_io(force);
}
BTW, pgstat_report_stat() treats "nowait" and "force" as the opposite
one, as follows.
/* don't wait for lock acquisition when !force */
nowait = !force;
Ryoga Yoshida
Commits
-
Fix behavior of "force" in pgstat_report_wal()
- 802fcb9ed166 15.5 landed
- 280f70221ba5 16.1 landed
- e221c0befb1b 17.0 landed